Application of organosilicon nanodots and their hydrogel sensors in the detection of tetrabromobisphenol A concentration

Abstract

This invention relates to the field of environmental pollutant detection, specifically to the application of organosilicon nanodots and their hydrogel sensors in the detection of tetrabromobisphenol A (TBA) concentration. The method includes: uniformly mixing an organosilicon nanodot stock solution with a sample to be tested, allowing it to stand in the dark to obtain a test solution; acquiring the sample fluorescence intensity value of the test solution at a specific wavelength, and the control fluorescence intensity value of a blank control solution without the test sample; calculating the quenching efficiency based on the sample fluorescence intensity value and the control fluorescence intensity value; and calculating the TBA concentration of the sample to be tested based on the quenching efficiency and a standard working curve; wherein the standard working curve is obtained by fitting the concentration of a TBA standard solution and its corresponding quenching efficiency. This invention aims to provide a simple, efficient, environmentally friendly, highly sensitive, and highly selective method for detecting TBA concentration.

Description

Technical Field

[0001] This invention relates to the field of environmental pollutant detection, specifically to the application of organosilicon nanodots and their hydrogel sensors in the detection of tetrabromobisphenol A concentration. Background Technology

[0002] Tetrabromobisphenol A (TBBPA) is one of the most widely used brominated flame retardants. Besides its use as a reactant in production, it is also used directly as an additive. This leads to the easy release of TBBPA into the environment during production, use, and recycling, resulting in its widespread distribution in environmental media. TBBPA can accumulate through the food chain. After ingestion, it competitively binds to thyroid transport proteins, causing endocrine disruption. Furthermore, related experiments have shown that TBBPA has various toxic effects, including neurotoxicity, immunotoxicity, growth and developmental toxicity, genotoxicity, and carcinogenicity. Therefore, developing time-efficient, highly sensitive, and selective methods for the trace detection of TBBPA to assess environmental TBBPA pollution levels is particularly important.

[0003] Currently, the detection of tetrabromobisphenol A mainly relies on techniques such as high-performance liquid chromatography (HPLC), liquid chromatography-mass spectrometry (LC-MS), and gas chromatography-mass spectrometry (GC-MS). While these methods ensure high accuracy and sensitivity, they suffer from drawbacks such as expensive equipment, complex pretreatment, long detection cycles, and high consumption of organic solvents, making them unsuitable for rapid on-site screening. Electrochemical analysis methods offer simple equipment but have poor interference resistance and cannot distinguish between coexisting bromine-based flame retardants and their derivatives, resulting in lower detection accuracy. Summary of the Invention

[0004] The present invention aims to provide a method for detecting tetrabromobisphenol A concentration that is simple, efficient, environmentally friendly, highly sensitive, and highly selective.

[0005] To address the aforementioned technical problems, as a first aspect, the present invention provides the application of organosilicon nanodots in the detection of tetrabromobisphenol A concentration.

[0006] Optionally, the application includes:

[0007] After mixing the organosilicon nanodot stock solution with the sample to be tested evenly, the solution was allowed to stand in the dark to obtain the test solution.

[0008] Obtain the sample fluorescence intensity value of the test liquid at a specific wavelength, and the control fluorescence intensity value of the blank control liquid without the test sample;

[0009] The quenching efficiency was calculated based on the fluorescence intensity values ​​of the sample and the control.

[0010] Based on the quenching efficiency and the standard working curve, the concentration of tetrabromobisphenol A in the sample to be tested is calculated; wherein, the standard working curve is obtained by fitting the concentration of the tetrabromobisphenol A standard solution and its corresponding quenching efficiency.

[0011] Optionally, the organosilicon nanodot stock solution is synthesized from silane and Bengal rose red via a hydrothermal method.

[0012] Optionally, the concentration of organosilicon nanodots in the test solution is 0.1 mg / mL.

[0013] Optionally, the concentration gradient of the tetrabromobisphenol A standard solution ranges from 0.1 to 50 µM.

[0014] Optionally, obtaining the sample fluorescence intensity value of the test liquid at a specific wavelength includes: using the fluorescence intensity of the test liquid at 538 nm as the sample fluorescence intensity value at an excitation wavelength of 310 nm.

[0015] As a second aspect, the present invention provides the application of a hydrogel sensor based on organosilicon nanodots in the detection of tetrabromobisphenol A concentration.

[0016] Optionally, the application includes:

[0017] The silicone nanodot-based hydrogel sensor was attached to the surface of standard samples with multiple concentration gradients. After being irradiated with a 310nm ultraviolet lamp, the green channel value attenuation rate of each standard sample was obtained.

[0018] The tetrabromobisphenol A concentration of multiple standard samples and their corresponding green channel value attenuation rates were fitted to obtain calibration curves.

[0019] The silicone nanodot-based hydrogel sensor is attached to the surface to be tested, and the green channel value attenuation rate of the surface to be tested is obtained.

[0020] Based on the attenuation rate of the green channel value of the surface under test and the calibration curve, the concentration of tetrabromobisphenol A on the surface under test is calculated.

[0021] Optionally, the method for preparing the silicone nanodot-based hydrogel sensor includes:

[0022] Organosilicon nanodots are added to a cellulose solution at a first temperature and mixed evenly to obtain a fluorescent active slurry; wherein the first temperature ranges from 0 to 4°C.

[0023] Polyvinyl alcohol is dissolved in deionized water and then mixed with the fluorescent active slurry at a second temperature. Acrylamide and N,N′-methylenebisacrylamide are added simultaneously, and nitrogen is purged to remove oxygen, resulting in an intermediate slurry. The second temperature ranges from 40 to 50°C.

[0024] Ammonium persulfate solution and tetramethylethylenediamine are added to the intermediate slurry, mixed evenly, and then injected into a mold for polymerization at a third temperature to obtain a polyacrylamide chemical crosslinking network. Subsequently, the polyacrylamide chemical crosslinking network is subjected to cyclic freezing and thawing to obtain a double-network hydrogel; wherein, the third temperature ranges from 40 to 50°C.

[0025] The dual-network hydrogel was soaked in deionized water and then freeze-dried under vacuum to obtain the silicone nanodot-based hydrogel sensor.

[0026] Optionally, the concentration of the organosilicon nanodots in the fluorescent active slurry is 0.3 mg / mL.

[0027] The advantages of this invention compared to related technologies include:

[0028] This invention employs organosilicon nanodots (OSiNDs) and their hydrogel sensors as fluorescent probes to detect the concentration of tetrabromobisphenol A (TBA). The detection principle is as follows: TBA exhibits strong absorption of 310 nm excitation light, resulting in an internal filtering effect. A portion of the 310 nm excitation light that should have been absorbed by OSiNDs is instead absorbed by TBA molecules, leading to a reduction in the light energy absorbed by OSiNDs and consequently, a decrease in the number of OSiNDs molecules that can be excited to higher energy states. Therefore, under 310 nm excitation light, the fluorescence emitted by OSiNDs can be efficiently quenched by TBA through a static quenching mechanism. As the concentration gradient of TBA increases, the proportion of excitation light absorbed increases, and the light energy absorbed by OSiNDs decreases proportionally, resulting in a gradient decrease in fluorescence intensity from strong to weak. Based on this gradient relationship, the concentration of TBA in the system can be quantitatively detected. Compared to traditional fluorescent probes containing toxic Cd or MoS2 materials, the organosilicon nanodot fluorescent probes provided in this invention have advantages such as being non-toxic, synthesized in one step, having a quantum yield of nearly 100%, high sensitivity, high selectivity, and visualization. Furthermore, the static quenching mechanism exhibits strong anti-interference capabilities, with a response rate of <5% to similar substances such as TBBPA-DHEE, TBBPA-BAE, and BPA. During detection, there is no need to consider temperature and pH coefficients, and the response signal is stable within a temperature range of 20 to 30°C and a pH range of 3 to 11, allowing for direct quantification. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the process for detecting tetrabromobisphenol A concentration using organosilicon nanodots in an embodiment of the present invention;

[0030] Figure 2This is a schematic diagram of the process for detecting the concentration of tetrabromobisphenol A using a hydrogel sensor based on organosilicon nanodots in an embodiment of the present invention.

[0031] Figure 3 The emission spectra of the 0.1 µM to 50 µM tetrabromobisphenol A standard solutions in Example 1 are shown in the range of 500 to 625 nm.

[0032] Figure 4 This is a standard working curve diagram for the liquid phase detection of organosilicon nanodots in Example 1;

[0033] Figure 5 The graph shows the response results of organosilicon nanodots to other common derivatives in Example 2;

[0034] Figure 6 The graph shows the response results of organosilicon nanodots in Example 3 within the pH range of 3 to 11;

[0035] Figure 7 This is a schematic diagram illustrating the construction process of the hydrogel sensor based on organosilicon nanodots in Example 4;

[0036] Figure 8 This is a microscopic SEM image of the silicone nanodot-based hydrogel sensor in Example 4;

[0037] Figure 9 This is a schematic diagram of the visualization detection of tetrabromobisphenol A using a dual-network hydrogel sensor combined with an RGB experimental platform in Example 4. Detailed Implementation

[0038] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below.

[0039] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit this application.

[0040] The term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to"; the term "based on" means "at least partially based on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; and the term "optionally" means "optional embodiments". Definitions of other terms will be given in the description below. It should be noted that the concepts of "first," "second," etc., mentioned in this invention are used to distinguish different objects, not to describe a specific order or hierarchy. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0041] Fluorescent probes offer advantages such as speed, low cost, and high sensitivity, along with high photoluminescence efficiency, no need for secondary modification, and simple synthesis methods, making them suitable for rapid on-site detection. However, in the detection of tetrabromobisphenol A (TBA) concentration, traditional fluorescent probes, generally based on nanomaterials such as CdTe and MoS2, suffer from problems including cytotoxicity, cumbersome synthesis steps, and poor photostability, making them difficult to deploy directly in complex environmental matrices. Furthermore, existing fluorescent detection technologies require surface molecular imprinting modification based on quantum dots. This modification necessitates using the target pollutant as a matrix material for template imprinting, leading to incomplete template elution during the final elution process. Consequently, the detection performance of the corresponding fluorescent probe is unstable, and the luminescence efficiency is reduced. Therefore, there is an urgent need to develop a fluorescent probe for the detection of TBA that is simple to process, highly efficient, environmentally friendly, and provides stable detection results.

[0042] To overcome the above problems, one embodiment of the present invention provides the application of organosilicon nanodots in the detection of tetrabromobisphenol A concentration.

[0043] It should be noted that organosilicon nanodots (OSiNDs) are a class of fluorescent nanomaterials, typically smaller than 10 nanometers, composed of organosilicon precursors. They possess advantages such as high photoluminescence quantum yield (>95%), narrow emission half-width, low phototoxicity, and surface functionalizability. Their main framework consists of Si-O-Si and Si-C bonds, and they usually contain a large number of organic groups (such as alkyl, amino, and carboxyl groups). These organic groups can originate from synthetic precursors (such as aminosilanes and mercaptosilanes) and become part of the nanodot structure. Due to their extremely small size, organosilicon nanodots typically exhibit a significant quantum confinement effect, emitting strong and tunable fluorescence when excited by external energy (such as ultraviolet light). For example, when an OSiNDs solution is irradiated with excitation light of a specific wavelength (such as 310 nm), the OSiNDs effectively absorb photons of that wavelength, causing electrons to transition from the ground state to the excited state. Subsequently, they relax back to the ground state, releasing energy and exhibiting strong fluorescence of a specific wavelength (such as green light).

[0044] In this embodiment, the inventors discovered that tetrabromobisphenol A (TBBPA) has a strong absorption effect on 310 nm excitation light, resulting in an internal filtering effect. A portion of the 310 nm excitation light that should have been absorbed by OSiNDs is absorbed by TCBPA molecules, leading to a reduction in the light energy absorbed by OSiNDs and consequently a decrease in the number of OSiNDs molecules that can be excited to higher energy states. Therefore, under 310 nm excitation light, the fluorescence emitted by OSiNDs can be efficiently quenched by TCBPA through a static quenching mechanism. As the concentration gradient of TCBPA increases, the proportion of excitation light absorbed by TCBPA increases, and the light energy absorbed by OSiNDs decreases proportionally, resulting in a gradient decrease in fluorescence intensity from strong to weak. Based on this gradient relationship, the concentration of TCBPA in the system can be quantitatively detected. Compared to traditional fluorescent probes containing toxic Cd or MoS2 materials, the organosilicon nanodot fluorescent probes provided in this invention offer advantages such as non-toxicity, one-step synthesis, near 100% quantum yield, high sensitivity, high selectivity, and visualization. Furthermore, the static quenching mechanism exhibits strong anti-interference capabilities, with a response rate of <5% to similar substances such as TBBPA-DHEE, TBBPA-BAE, and BPA. Because the fluorescence quenching mechanism is static, fluorescence lifetime measurements show that the lifetime of OSiNDs remains unchanged at 4.2 ns before and after the addition of tetrabromobisphenol A. Therefore, the dynamic quenching temperature coefficient does not need to be considered during detection, and direct quantification is possible within the room temperature range of 20 to 30°C.

[0045] In some alternative embodiments, refer to Figure 1 As shown, the application of organosilicon nanodots in the detection of tetrabromobisphenol A concentration may specifically include the following steps:

[0046] Step S1: After thoroughly mixing the organosilicon nanodot stock solution with the sample to be tested, allow it to stand in the dark to obtain the test solution. The organosilicon nanodot stock solution can be synthesized from silane and Bengal rose red via a hydrothermal method. As an example, the specific preparation method includes: dissolving Bengal rose red and silane in deionized water, stirring at room temperature, transferring to a polytetrafluoroethylene liner, and hydrothermally reacting at 160°C for 4 h. The reaction solution is then preliminarily filtered through a filter membrane and dialyzed for 24 h to obtain an organosilicon nanodot stock solution with a fluorescence quantum yield ≥95%. The silane can be 3-(2-aminoethylamino)propyltrimethoxysilane.

[0047] In some optional embodiments, the concentration of organosilicon nanodots in the test solution is 0.1 mg / mL. At this concentration, the detection limit of tetrabromobisphenol A in the sample is as low as 12.6 nM. It should be noted that the concentration of organosilicon nanodots in the aforementioned stock solution is 1 mg / mL. When preparing the test solution, the stock solution should first be diluted to a concentration of 0.2 mg / mL before mixing with the sample to be tested, so that the final concentration of organosilicon nanodots in the test solution is 0.1 mg / mL. In actual detection, the test solution shows stable signal over a wide pH range, so generally no additional pH adjustment is required. Preferably, if the pH of the sample to be tested is <5 or >9, the pH of the final test solution can be adjusted to 7.0 ± 0.2 using a 10 mM phosphate buffer.

[0048] Step S2: Obtain the sample fluorescence intensity value of the test solution at a specific wavelength, and the control fluorescence intensity value of the blank control solution without the test sample. Specifically, the absorption spectrum of the test solution in the range of 300 to 600 nm is recorded in advance using a spectrophotometer to confirm that the characteristic absorption peak of tetrabromobisphenol A at 310 nm has not shifted. Then, at an excitation wavelength of 310 nm, the emission spectrum of the test solution in the wavelength range of 500 to 625 nm is measured using a fluorescence spectrophotometer, and the fluorescence intensity of the test solution at 538 nm is taken as the sample fluorescence intensity value. Similarly, the control fluorescence intensity value of the blank control solution is determined according to the above method. It should be noted that the composition of the blank control solution is the same as that of the test solution, except that it does not contain the test sample, and the concentration of organosilicon nanodots in the blank control solution and the test solution is the same.

[0049] Step S3: Calculate the quenching efficiency based on the sample fluorescence intensity value and the control fluorescence intensity value. Specifically, using the sample fluorescence intensity value obtained in step S2 and the control fluorescence intensity value of the blank control solution as a benchmark, calculate the quenching efficiency according to the following formula:

[0050] Q= ;

[0051] In the above formula, Q represents the quenching efficiency, and F represents the sample fluorescence intensity value. The value represents the control fluorescence intensity.

[0052] Step S4: Calculate the concentration of tetrabromobisphenol A in the sample to be tested based on the quenching efficiency and the standard working curve; wherein, the standard working curve is obtained by fitting the concentration of the tetrabromobisphenol A standard solution and its corresponding quenching efficiency.

[0053] Specifically, the concentration gradient of the tetrabromobisphenol A standard solution ranges from 0.1 µM to 50 µM. The fitting process is performed according to steps S1 to S3 above. First, 1 mL of each of the multiple gradient tetrabromobisphenol A standard solutions (0.1 µM to 50 µM) is prepared using methanol and water (mixed in a 1:1 volume ratio) as a mixed solvent. Then, 10 µL of organosilicon nanodot stock solution is added to each concentration gradient of the tetrabromobisphenol A standard solution, and after thorough mixing, the fluorescence intensity values ​​of the samples at each concentration gradient are measured. The quenching efficiency is then calculated based on the fluorescence intensity values ​​of each sample and the control fluorescence intensity values. Finally, a standard working curve is obtained by fitting the concentration of each tetrabromobisphenol A standard solution as the x-axis and the corresponding quenching efficiency as the y-axis using the least squares method. Therefore, by substituting the quenching efficiency of the test solution determined in step S3 into this standard working curve, the concentration of tetrabromobisphenol A in the sample to be tested can be directly calculated.

[0054] In this embodiment of the invention, the organosilicon nanodot stock solution can be used for rapid screening of tetrabromobisphenol A in wastewater from electronic product dismantling workshops, toy surface rinsing solutions, and soil extracts. It should be noted that since the standard curve is determined based on a concentration gradient range of 0.1 to 50 µM, for samples with concentrations exceeding this range, they can be diluted by a certain factor before being measured according to steps S1 to S4 above. For example, electronic product wastewater, toy rinsing solutions, and soil extracts can be measured after simple dilution or C18 solid-phase extraction. For instance, for soil samples, a methanol / water (1:1) mixture can be added at a ratio of 1:5 (m / v), sonicated for 30 min, centrifuged at 4000 r / min for 10 min, and the supernatant filtered through a 0.22 µm filter membrane before being measured according to steps S2 to S4.

[0055] Another embodiment of the present invention also provides the application of a hydrogel sensor based on organosilicon nanodots in the detection of tetrabromobisphenol A concentration.

[0056] Due to the challenges of liquid-phase probes, such as difficulty in recovery, poor on-site adaptability, and difficulty in directly adhering to irregular detection surfaces, this embodiment utilizes a liquid-phase fluorescence detection method based on organosilicon nanodots to further construct a flexible, visualized, and reusable hydrogel sensor for rapid on-site screening and determination of tetrabromobisphenol A (TBBPA). Specifically, organosilicon nanodots are anchored in a dual-network hydrogel, and the sensor can be recovered and reused by eluting the used hydrogel. Furthermore, based on the gradient detection specificity of OSiNDs for TPBPA, the brightness of the hydrogel sensor can be gradiented from bright green to dark green, thus achieving visualized detection. The PVA material in the hydrogel also imparts tensile properties, enabling it to adhere to irregular surfaces for detection.

[0057] Specifically, when applying a hydrogel sensor based on organosilicon nanodots to the detection of tetrabromobisphenol A concentration, refer to Figure 2 As shown, the specific steps may include:

[0058] Step 1: The silicone nanodot-based hydrogel sensor was attached to the surface of standard samples with multiple concentration gradients. After irradiation with a 310 nm UV lamp, the green channel value attenuation rate of each standard sample was obtained.

[0059] Specifically, the fabrication method of the hydrogel sensor based on organosilicon nanodots may include:

[0060] (1) Add organosilicon nanodots to the cellulose solution at the first temperature and mix evenly to obtain a fluorescent active slurry; wherein the first temperature ranges from 0 to 4°C and the mass fraction of the cellulose solution is from 1 to 3 wt%.

[0061] Specifically, the organosilicon nanodot stock solution can be freeze-dried into a powder state, and then the organosilicon nanodot powder can be added to a cellulose solution to prepare a fluorescent active slurry. The concentration of organosilicon nanodots in the fluorescent active slurry is 0.3 mg / mL. In this step, the Si-OH groups of the organosilicon nanodots covalently couple with the C6-OH groups of cellulose.

[0062] (2) After dissolving polyvinyl alcohol in deionized water, it is mixed with fluorescent active slurry at a second temperature, and acrylamide and N,N′-methylenebisacrylamide are added at the same time. Nitrogen is passed through to remove oxygen, and intermediate slurry is obtained. The range of the second temperature is 40 to 50°C.

[0063] (3) Add ammonium persulfate solution and tetramethylethylenediamine to the intermediate slurry, mix them evenly, inject them into the mold and carry out the polymerization reaction at the third temperature to obtain a polyacrylamide chemical crosslinking network. Then, the polyacrylamide chemical crosslinking network is subjected to cyclic freezing and thawing to obtain a double network hydrogel; wherein, the range of the third temperature is 40 to 50°C.

[0064] (4) The double-network hydrogel was soaked in deionized water and then freeze-dried under vacuum to remove unreacted monomers, thus obtaining a hydrogel sensor. The porosity of the hydrogel sensor is 60 to 80%, the saturated water content is ≥800%, and it emits 538 nm saturated green fluorescence under 310 nm excitation.

[0065] Step 2: Fit the tetrabromobisphenol A concentration of multiple standard samples and their corresponding green channel value attenuation rate to obtain the calibration curve.

[0066] Furthermore, in this step, a calibration curve for tetrabromobisphenol A can be created and visualized using an RGB experimental platform. When creating the calibration curve, similar to the standard working curve, multiple standard samples within a certain concentration gradient range (0.1 to 50 µM) can be prepared first. Then, the green channel values ​​of each standard sample and the blank control sample are obtained using the RGB experimental platform, and the green channel value attenuation rate is calculated. The green channel value attenuation rate is calculated according to the following formula:

[0067] ΔG%= ;

[0068] In the above formula, ΔG% is the attenuation rate of the green channel value. The green channel value is for the standard sample. The green channel value is for the blank control sample.

[0069] Step 3: Attach the silicone nanodot-based hydrogel sensor to the surface to be tested and obtain the attenuation rate of the green channel value of the surface to be tested.

[0070] Step 4: Based on the attenuation rate of the green channel value of the surface under test and the calibration curve, calculate the concentration of tetrabromobisphenol A on the surface under test.

[0071] In this embodiment, a flexible hydrogel sensor is prepared by covalently anchoring organosilicon nanodots to a regenerated cellulose-polyvinyl alcohol / polyacrylamide dual-network hydrogel, enabling in-situ enrichment, visualized quantitative detection, and multiple recycling of tetrabromobisphenol A (TBA) in complex matrices. In the dual-network hydrogel, polyvinyl alcohol undergoes multiple freeze-thaw cycles to form physically cross-linked crystal domains, endowing the hydrogel sensor with high elasticity and stretchability. Furthermore, the strong hydrogen bonds formed by the freeze-thaw cross-linking of polyvinyl alcohol promote the adsorption of TBA. Acrylamide undergoes free radical polymerization under the action of N,N′-methylenebisacrylamide, ammonium persulfate, and tetramethylethylenediamine to construct a rigid chemically cross-linked network. Regenerated cellulose type II provides a porous framework and C6-OH active sites, covalently coupling with the Si-OH on the surface of the organosilicon nanodots to form a fluorescent sensing interface. After attaching the hydrogel sensor to the test surface, TBA diffuses from the test surface into the hydrogel, quenching the fluorescence of the organosilicon nanodots in the hydrogel, causing the color to gradually change from bright green to dark green. Furthermore, the hydrogel sensor can be connected to a smartphone to directly read the G value for on-site quantitative detection. In this embodiment, the hydrogel sensor exhibits a mass recovery rate >95%, a fluorescence intensity recovery rate >96%, and a cycle life ≥20 after drying at 60℃ for 12 hours. The detection limit of the hydrogel sensor for tetrabromobisphenol A is 0.1 µM. 2 ≥0.99; the response rate to TBBPA-DHEE, TBBPA-BAE, BPA, and BP is <5%, indicating good selectivity.

[0072] The present invention will be described in detail below through specific embodiments:

[0073] Example 1

[0074] This embodiment provides the application of organosilicon nanodots in the detection of tetrabromobisphenol A concentration, specifically including the following steps:

[0075] (I) Preparation of Organosilicon Nanodots

[0076] 30 mg of Bengal rose red and 1 mL of 3-(2-aminoethylamino)propyltrimethoxysilane were dissolved in 4 mL of deionized water and stirred at room temperature for 5 min. The solution was then transferred to a 25 mL polytetrafluoroethylene liner and hydrothermally reacted at 160 °C for 4 h. After cooling, the solution was initially filtered through a 0.22 µm filter membrane and then dialyzed through a 500 Da dialysis bag for 24 h to obtain a light brown, clear stock solution of organosilicon nanodots (1 mg / mL, PLQY ≈ 100%). The organosilicon nanodots prepared in this example were spherical with a particle size of 2 to 5 nm.

[0077] (II) Standard Working Curve Creation

[0078] Prepare 1 mL of each of the 0.2 µM to 100 µM gradient tetrabromobisphenol A standard solutions using a 1:1 mixture of methanol and water. Sonicate for 1 min to completely dissolve the solute. Add 1 mL of a 0.2 mg / mL stock solution of organosilicon nanodots to each of the 1 mL tetrabromobisphenol A standard solutions, sonicate for 5 min to mix, and incubate at 25 °C in the dark for 2 h to obtain a mixed solution. Therefore, the concentration of organosilicon nanodots in the mixed solution is 0.1 mg / mL, and the concentration gradient of tetrabromobisphenol A is 0.1 µM to 50 µM.

[0079] like Figure 3 As shown, with 310 nm as the excitation wavelength, the emission spectra of each mixture from 500 to 625 nm were measured using a fluorescence spectrophotometer, and the fluorescence intensity F at 538 nm was read for each mixture; simultaneously, the quenching efficiency Q was calculated based on the fluorescence intensity F0 of the blank control group without tetrabromobisphenol A. Figure 4 As shown, the horizontal axis represents the concentration of tetrabromobisphenol A, and the vertical axis represents the quenching efficiency. The standard operating curve equation in this embodiment is y = 0.04679x + 0.00995, R0 2 =0.997, detection limit is 12.6 nM.

[0080] (III) Sample Testing

[0081] Add 0.1 mL of organosilicon nanodot stock solution to 1 mL of the sample to be tested, sonicate for 5 min to mix, and let stand at 25℃ in the dark for 2 h to obtain a mixture. Using 310 nm as the excitation wavelength, measure the emission spectrum of each mixture from 500 to 625 nm using a fluorescence spectrophotometer, and read the fluorescence intensity F at 538 nm for each mixture; simultaneously, calculate the quenching efficiency Q based on the fluorescence intensity F0 of the blank control group without tetrabromobisphenol A. Substitute the calculated quenching efficiency into the standard working curve equation in step (II) to calculate the concentration of the sample to be tested as 0.23 μmol / L.

[0082] Example 2

[0083] In this embodiment, the same concentrations of TBBPS, TBBPA, BPA, TBBPA-DHEE, TBBPA-BAE, and BP were added to a 0.1 mg / mL organosilicon nanodot stock solution, and the fluorescence intensity was detected and the quenching efficiency was calculated following the steps in Example 1. The results are as follows: Figure 5 As shown, the relative errors of all interfering substances except TBBPS are <5%, and TBBPS, as a substitute for tetrabromobisphenol A, is not often found in the environment simultaneously with tetrabromobisphenol A. This indicates that the detection method in Example 1 has good selectivity for tetrabromobisphenol A in most environments.

[0084] Example 3

[0085] In this embodiment, a mixture of methanol and water (1:1 equal volume mixture) was used as the solvent. HCl / NaOH was added to adjust the pH to 3-11. Then, 5µM tetrabromobisphenol A and organosilicon nanodot stock solution were added. Fluorescence intensity was detected and quenching efficiency was calculated. The results are as follows: Figure 6 As shown, by Figure 6 It can be seen that the mixed solution has a stable signal in the pH range of 3 to 11, and the fluorescence intensity of the organosilicon nanodot stock solution changes by less than 2% in the methanol / water mixed solvent with a pH range of 6.5 to 7.5. Therefore, no additional pH adjustment is required in actual detection.

[0086] Example 4

[0087] This embodiment provides the application of a hydrogel sensor based on organosilicon nanodots in the detection of tetrabromobisphenol A concentration, specifically including the following steps:

[0088] (I) Preparation of fluorescent active paste

[0089] 5 g of cellulose was added to a mixed solvent of NaOH / urea / water (7 wt% / 12 wt% / 81 wt%) and rapidly dissolved at -12 °C, then regenerated at -20 °C for 12 h to obtain a 2 wt% cellulose solution. The organosilicon nanodot stock solution was freeze-dried into a powder state. Then, 0.3 mg of organosilicon nanodot powder was added to 10 ml of the cellulose solution at 0 °C, followed by vigorous stirring at 60 °C for 1 h, and then allowed to stand at room temperature for 2 h. The conjugate was placed in a dialysis bag with a molecular weight cutoff of 3.5 kDa, immersed in deionized water, and dialyzed at 4 °C with stirring for 48 h, changing the water every 12 h to obtain a fluorescently active slurry.

[0090] (II) Preparation of dual-network hydrogels

[0091] like Figure 7 As shown, 1g of polyvinyl alcohol (PVA, Mw of 85000 to 124000) was dissolved in 9mL of deionized water at 90℃. After cooling to 45℃, it was mixed with the fluorescent active slurry from step (I) at a volume ratio of 1:1. 8.5g was taken out and 1.5g of acrylamide (AM) and 0.010g of N,N′-methylenebisacrylamide (MBA) were added. Nitrogen was purged for 15min to remove oxygen, and an intermediate slurry was obtained.

[0092] Subsequently, 0.1 mL of ammonium persulfate solution (APS, 0.16 g / mL) and 10 µL of tetramethylethylenediamine were added sequentially to the intermediate slurry. After thorough mixing, the mixture was rapidly poured into a 1 mm thick polytetrafluoroethylene mold. The mold was then placed in an oven at 45 °C for free radical polymerization for 2 h to construct a polyacrylamide chemical crosslinking network. The polyacrylamide chemical crosslinking network was then frozen at -20 °C for 8 h and then thawed at room temperature for 4 h. This freeze-thaw cycle was repeated three times to obtain a dual-network hydrogel, which consists of a polyacrylamide network (PAM) and a polyvinyl alcohol network (PVA).

[0093] The dual-network hydrogel was soaked in deionized water for 24 hours to remove unreacted monomers, and then freeze-dried under vacuum for 12 hours to obtain the hydrogel sensor. The microscopic SEM image of the dual-network hydrogel sensor prepared in this embodiment is shown below. Figure 8 As shown, its porosity is 60 to 80%, its saturated water content is ≥800%, and it emits 538nm saturated green fluorescence under 310nm excitation.

[0094] (III) Detection of the surface to be tested

[0095] like Figure 9 As shown, an RGB experimental platform was built using a color picker to create and visualize the calibration curve for tetrabromobisphenol A. In creating the calibration curve, multiple standard samples with a concentration gradient range (0.1 to 50 µM) were prepared. The sensor was attached to the surface of the standard samples, and after irradiation with a 310 nm UV lamp, ambient light was corrected using a standard white board, resulting in a visible gradient from bright green to dark green. Simultaneously, the green channel value was acquired using the RGB experimental platform on a mobile phone, and the green channel value attenuation rate was calculated. The concentration of each standard sample and its corresponding green channel value attenuation rate were fitted to obtain the calibration curve equation: y = 43.326 + 0.338x, R0. 2 =0.991.

[0096] The hydrogel sensor from step (II) is further cut into square pieces with a diameter of 5-10 mm and encapsulated in PET transparent tape to create a portable patch sensor. The sensor is attached to the surface to be tested, and after irradiation with a 310 nm ultraviolet lamp, the ambient light is calibrated using a standard white board. The green channel value is obtained through the RGB experimental platform of a mobile phone, and the green channel value attenuation rate is calculated. Based on the calibration curve equation and the green channel value attenuation rate, the concentration of tetrabromobisphenol A in the surface to be tested is calculated to be 0.65 μmol / L.

[0097] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. Use of organosilica nanodots in the detection of tetrabromobisphenol A, characterized in that, The application relates to a method for detecting tetrabromobisphenol A (TBBPA) in a sample, comprising the following steps: mixing an organic silicon nanodot stock solution with a sample to be detected, and then avoiding light and standing to obtain a sample to be detected; wherein the organic silicon nanodot stock solution is synthesized by a hydrothermal method through silane and rose Bengal; obtaining a sample fluorescence intensity value of the sample to be detected at a specific wavelength, and a control fluorescence intensity value of a blank control solution without the sample to be detected; calculating a quenching efficiency based on the sample fluorescence intensity value and the control fluorescence intensity value; calculating a TBBPA concentration of the sample to be detected based on the quenching efficiency and a standard working curve; wherein the standard working curve is fitted by a TBBPA standard solution concentration and a corresponding quenching efficiency. The concentration of the organic silicon nanodots in the sample to be detected is 0.1 mg / mL. The concentration gradient range of the TBBPA standard solution is 0.1 to 50 muM. The method for obtaining the sample fluorescence intensity value of the sample to be detected at the specific wavelength comprises the following steps: under an excitation wavelength of 310 nm, taking a fluorescence intensity value of the sample to be detected at 538 nm as the sample fluorescence intensity value. The organic silicon nanodots are synthesized by a hydrothermal method through silane and rose Bengal.

2. Use of the silicone nanodots according to claim 1 for the detection of tetrabromobisphenol A, characterized in that, The application further relates to a method for detecting TBBPA on a surface, comprising the following steps: attaching an organic silicon nanodot-based hydrogel sensor to the surface to be detected; obtaining a green channel value decay rate of the surface to be detected after irradiation by a 310 nm ultraviolet lamp; and calculating a TBBPA concentration of the surface to be detected based on the green channel value decay rate of the surface to be detected and a calibration curve.

3. Use of the silicone nanodots according to claim 1 in the detection of tetrabromobisphenol A, characterized in that, The preparation method of the organic silicon nanodot-based hydrogel sensor comprises the following steps: adding organic silicon nanodots to a cellulose solution at a first temperature, and uniformly mixing to obtain a fluorescent active slurry; wherein the first temperature ranges from 0 to 4 DEG C; dissolving polyvinyl alcohol in deionized water, mixing with the fluorescent active slurry at a second temperature, and adding acrylamide and N,N'-methylenebisacrylamide while deoxidizing by nitrogen to obtain an intermediate slurry; wherein the second temperature ranges from 40 to 50 DEG C; adding ammonium persulfate solution and tetramethylethylenediamine to the intermediate slurry, uniformly mixing, pouring into a mold, and performing a polymerization reaction at a third temperature to obtain a polyacrylamide chemical crosslinking network, and then obtaining a double-network hydrogel after the polyacrylamide chemical crosslinking network is subjected to cyclic freezing and thawing; wherein the third temperature ranges from 40 to 50 DEG C; and soaking the double-network hydrogel in deionized water and vacuum freeze-drying to obtain the organic silicon nanodot-based hydrogel sensor.

4. The use of silicone nanodots according to claim 1 in the detection of tetrabromobisphenol A, characterized by, The concentration of the organic silicon nanodots in the fluorescent active slurry is 0.3 mg / mL.

5. Use of a hydrogel sensor based on organosilica nanodots for the detection of tetrabromobisphenol A concentration, characterized in that, ​ 6. Use of the organosilica nanodot-based hydrogel sensor according to claim 5 for the detection of tetrabromobisphenol A concentration, characterized in that, ​ ​ ​ ​ ​ 7. Use of the organosilica nanodot-based hydrogel sensor according to claim 6 for the detection of tetrabromobisphenol A concentration, characterized in that, ​ ​ ​ ​ ​ 8. Use of the organosilica nanodot-based hydrogel sensor according to claim 7 for the detection of tetrabromobisphenol A concentration, characterized in that, ​

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